Where is my truck leaking water from?

As we were moving someone else had to drive my ford expedition but in doing so the drove it in the wrong gear it ran hot and cut off on the highway we didn't get it homw the next day til after filling it with water now the truck is drive able but we always have to keep water in it so it doesn't overheat that seems to be the only problem other than that everything is fine someone please tell me what this is

You might have warped the cylinder head due to overheating. Run a compression test.

You probably blew a head gasket.

Hi Radiator in most cases.

Usually its the water pump, and they're hard to see leaking. You may need to crawl under the front of the vehicle and look up, as the weep hole is behind the pump itself and the water will run straight down, then the radiator fan blows it backwards, hence, the "hard to find" syndrome. Good luck, you'll see it somewhere. Best to just fill it up with coolant and let is sit idling for 20 minutes or so, then start your hunt!

The water pump is easy to check. Look for a trail of white residue which is the trail of antifreeze from the leak. If it's not the water pump leaking it will be soon if you are only putting water into the cooling system. Antifreeze has a lubricant that is needed to lube and protect the water pump seal and the lack of a rust inhibitor which is also in the antifreeze will cause the inside of the motor to rust up in a few days and the rust then plugs up the radiator and heater core. Better just get the vehicle to a mechanic right away before you mess anything else up. A head gasket job costs $2,000 and you are well on your way to spending that money soon!